Evaluation of neutropenia and neutrophilia in preterm infants

Leukopenia and Neutropenia at Birth and Sepsis in Preterm Neonates of <32 Weeks' Gestation

OBJECTIVE

This study aimed to evaluate associations between leukopenia or neutropenia at birth and risk of sepsis in very preterm neonates.

STUDY DESIGN

We conducted a retrospective unmatched cohort study of neonates of <32 weeks' gestation. Those with leukopenia (≤5,000/µL) were compared with a unmatched cohort without leukopenia. Comparisons were also made for patients with neutropenia and without neutropenia. The outcomes were early-onset sepsis, late-onset sepsis, and mortality.

RESULTS

We identified 271 neonates with leukopenia at birth and 271 without. Multivariable analyses identified higher odds of early-onset sepsis (adjusted odds ratio [AOR] = 4.85, 95% confidence interval [CI]: 1.29-18.20) in leukopenic neonates. Of neonates with leukopenia, 183 had both leukopenia and neutropenia and were associated with the highest odds of early-onset sepsis (AOR = 6.94, 95% CI: 1.77-27.15) compared with those with neither or with either alone.

CONCLUSION

Leukopenia, neutropenia, and both leukopenia and neutropenia at birth were associated with early-onset sepsis in very preterm neonates.

KEY POINTS

· Leukopenia and neutropenia combined at birth was associated with highest odds of early-onset sepsis.. · Leukopenia or neutropenia were associated with sepsis in preterm neonates.. · The risk of infection persist throughout neonatal stay in NICU..

Premature Birth Infants Present Elevated Inflammatory Markers in the Meconium

Introduction: Prematurity, a well-established risk factor for various intestinal diseases in newborns, results in increased morbidity and mortality. However, the intestinal inflammatory status of preterm (PT) infants has been poorly characterized. Here we have broadly described the intestinal and systemic inflammatory status of PT children. Materials and Methods: Meconium and plasma from 39 PT and 32 full term (T) newborns were studied. Fecal calprotectin, polymorphonuclear leukocyte elastase (PMN-E), TNF, IL-17A, IL-8, IP-10, MCP-1, MIP-1, IL-1β, IL-1α, and E-selectin and the enzymatic activities of myeloperoxidase (MPO) and alkaline phosphatase (AP) in meconium were measured. Plasma levels of AP, hepatocyte growth factor, nerve growth factor (NGF), proinflammatory cytokines, leptin, adiponectin, PAI-1, and resistin were also determined. Correlations with gestational age (GA) and birth weight (BW) were studied. Results: Neutrophil derived PMN-E, MPO and calprotectin were increased in the meconium of PT compared to T newborns, while AP was decreased. No significant differences were found in other inflammatory parameters. Considering data from all children, GA and BW showed inverse correlation with neutrophil markers, while AP directly correlated with BW. Plasma levels of IL-1β and NGF were enhanced in PT infants, and were also negatively correlated with BW. PT children additionally showed neutropenia and decreased adiponectin, leptin, haematocrit, and haemoglobin. These parameters (neutrophils, adiponectin, and so forth) were positively correlated with GA and BW, while IL-8, MCP-1, PAI-1, and plasma AP were negatively correlated. PT children showing postnatal morbidity exhibited increased meconium MPO and MIP-1α. Conclusion: PT neonates present a significant elevation of intestinal inflammatory parameters, characterized by the presence of neutrophil markers, associated with mild systemic inflammation.

Adjunctive therapy to treat neonatal sepsis

Introduction: Neonatal sepsis (NS) is a very severe condition that causes significant morbidity and mortality.Areas covered: To overcome the limits of antibiotic therapy and improve NS outcomes, measures chosen among those theoretically able to improve host defenses or positively interfere with deleterious immune responses could be suggested. This paper discusses the mechanisms of action of these measures, whether their efficacy in prophylaxis justifies use in NS therapy and their impact.Expert opinion: NS remains a relevant problem despite the availability of antibiotics effective against the most common agents and the introduction of effective preventive measures such as group B Streptococcus prenatal screening and intrapartum antibiotic prophylaxis. This explains why attempts to introduce new prophylactic and therapeutic measures have been made. Unfortunately, none of the measures suggested and tested to date can be considered a definitive advance. It is highly likely that in the future, new measures will be proposed according to the increase in the knowledge of the characteristics of immune system function in preterm infants and the methods to modulate unproper immune responses.

Severe neutropenia in a breastfed infant: a case report and discussion of the differential diagnosis

Neonatal neutropenia is regularly seen with variable etiology. We describe a breastfed infant with maternal medication use as a probable cause of neonatal neutropenia. An 8 days old exclusively breastfed female infant of Arab-Berber descent was referred to our hospital because of an infection of the umbilicus. Complete blood count showed a picture of severe isolated neutropenia. After initiating intravenous antibiotic treatment, the infection quickly resolved, but the isolated neutropenia persisted. Bone marrow aspiration indicated severe congenital neutropenia. The mother was known to have Crohn’s disease, treated with methylprednisolone and adalimumab up to 3 months before delivery, and latent tuberculosis, for which she used isoniazid postnatally. Breast-feeding was terminated and filgrastim was started, with an increase of the neutrophilic count. After several weeks, filgrastim could be terminated. Bone marrow and complete blood count were repeated and were completely normal. This case report describes a very young breastfed female infant with severe neutropenia, causing an infection, in which maternal adalimumab use could not be excluded as a possible cause. Maternal isoniazid use is highly unlikely.

Clinical features and prognostic factors of early-onset sepsis: a 7.5-year experience in one neonatal intensive care unit

Purpose

In this study, we investigated the clinical features and prognostic factors of early-onset sepsis (EOS) in neonatal intensive care unit (NICU) patients.

Methods

A retrospective analysis was conducted on medical records from January 2010 to June 2017 (7.5 years) of a university hospital NICU.

Results

There were 45 cases of EOS (1.2%) in 3,862 infants. The most common pathogen responsible for EOS was group B Streptococcus (GBS), implicated in 10 cases (22.2%), followed by Escherichia coli, implicated in 9 cases (20%). The frequency of gram-positive sepsis was higher in term than in preterm infants, whereas the rate of gram-negative infection was higher in preterm than in term infants (P<0.05). The overall mortality was 37.8% (17 of 45), and 47% of deaths occurred within the first 3 days of infection. There were significant differences in terms of gestational age (26.8 weeks vs. 35.1 weeks) and birth weight (957 g vs. 2,520 g) between the death and survival groups. After adjustments based on the difference in gestational age and birth weight between the 2 groups, gram-negative pathogens (odds ratio [OR], 42; 95% confidence interval [CI], 1.4–1,281.8) and some clinical findings, such as neutropenia (OR, 46; 95% CI, 1.3–1,628.7) and decreased activity (OR, 34; 95% CI, 1.8–633.4), were found to be associated with fatality.

Conclusion

The common pathogens found to be responsible for EOS in NICU patients are GBS and E. coli. Gram-negative bacterial infections, decreased activity in the early phase of infection, and neutropenia were associated with poor outcomes.

Bloodstream Infections

Bacteremia and sepsis are conditions associated with high mortality and are of great impact to health care operations. Among the top causes of mortality in the United States, these conditions cause over 600 fatalities each day. Empiric, broad-spectrum treatment is a common but often a costly approach that may fail to effectively target the correct microbe, may inadvertently harm patients via antimicrobial toxicity or downstream antimicrobial resistance. To meet the diagnostic challenges of bacteremia and sepsis, laboratories must understand the complexity of diagnosing and treating septic patients, in order to focus on creating algorithms that can help direct a more targeted approach to antimicrobial therapy and synergize with existing clinical practices defined in new Surviving Sepsis Guidelines. Significant advances have been made in improving blood culture media; as yet no molecular or antigen-based method has proven superior for the detection of bacteremia in terms of limit of detection. Several methods for rapid molecular identification of pathogens from blood cultures bottles are available and many more are on the diagnostic horizon. Ultimately, early intervention by molecular detection of bacteria and fungi directly from whole blood could provide the most patient benefit and contribute to tailored antibiotic coverage of the patient early on in the course of the disease. Although blood cultures remain as the best means of diagnosing bacteremia and candidemia, complementary testing with antigen tests, microbiologic investigations from other body sites, and histopathology can often aid in the diagnosis of disseminated disease, and application of emerging nucleic acid test methods and other new technology may greatly impact our ability to bacteremic and septic patients, particularly those who are immunocompromised.

Preeclampsia and Inflammatory Preterm Labor Alter the Human Placental Hematopoietic Niche

BACKGROUND

The human placenta is a source of hematopoietic stem and progenitor cells (HSPCs). The RUNX1 transcription factor is required for the formation of functional HSPCs. The impact of preeclampsia (PE) and preterm labor (PTL, spontaneous preterm labor [sPTL] and inflammatory preterm labor [iPTL]) on HSPC localization and RUNX1 expression in the human placenta is unknown.

METHODS

We compared the frequency and density of HSPC in control samples from sPTL (n = 6) versus PE (n = 6) and iPTL (n = 6). We examined RUNX1 protein and RNA expression in placentas from normal pregnancies (5-22 weeks, n = 8 total) and in placentas from the aforementioned pregnancy complications (n = 5/group).

RESULTS

Hematopoietic stem and progenitor cells were rare cell types, associated predominantly with the vasculature of placental villi. The HSPC density was greater in the chorionic plate (CP) compared to the villi (P < .001) and greater in PE and iPTL samples as compared to controls within the CP (not significant) and overall (P < .05). During the fetal period, RUNX1 was expressed in the mesenchyme of the CP and villi. Inflammatory PTL samples were more likely to exhibit intraluminal RUNX1(+) cell populations (P < .001) and RUNX1(+) cell clusters attached to arterial endothelial cells.

CONCLUSION

Placental HSPCs likely arise from hematopoietic niches comprised RUNX1(+) mesenchyme and vascular endothelium. Pregnancy complications that result in preterm birth differentially affect placental HSPC localization and RUNX1 expression. Our results support previous findings that inflammation positively regulates hematopoiesis. We present new evidence that hemogenic endothelium may be active at later stages of human fetal development in the context of inflammation.

Oral antibiotics increase blood neutrophil maturation and reduce bacteremia and necrotizing enterocolitis in the immediate postnatal period of preterm pigs

Immature immunity may predispose preterm neonates to infections and necrotizing enterocolitis (NEC). Intravenous antibiotics are frequently given to prevent and treat sepsis, while oral antibiotics are seldom used. We hypothesized that oral antibiotics promote maturation of systemic immunity and delay gut bacterial colonization and thereby protect preterm neonates against both NEC and bacteremia in the immediate postnatal period. Preterm pigs were given formula and administered saline (CON) or broad-spectrum antibiotics orally (ORA) or systemically (SYS) for 5 d after birth. Temporal changes in blood parameters and bacterial composition in the intestine, blood and immune organs were analyzed. Newborn preterm pigs had few blood neutrophils and a high frequency of progenitor cells. Neutrophils gradually matured after preterm birth with increasing CD14 and decreasing CD172a expressions. Preterm neutrophil and monocyte TLR2 expression and TLR2-mediated blood cytokine responses were low relative to adults. ORA pigs showed enhanced blood neutrophil maturation with reduced cell size and CD172a expression. Only ORA pigs, but not SYS pigs, were protected from a high density of gut Gram-positive bacteria, high gut permeability, Gram-positive bacteremia and NEC. Neonatal oral antibiotics may benefit mucosal and systemic immunity via delayed gut colonization and enhanced blood neutrophil maturation just after preterm birth.

Affect of Early Life Oxygen Exposure on Proper Lung Development and Response to Respiratory Viral Infections

Children born preterm often exhibit reduced lung function and increased severity of response to respiratory viruses, suggesting that premature birth has compromised proper development of the respiratory epithelium and innate immune defenses. Increasing evidence suggests that premature birth promotes aberrant lung development likely due to the neonatal oxygen transition occurring before pulmonary development has matured. Given that preterm infants are born at a point of time where their immune system is also still developing, early life oxygen exposure may also be disrupting proper development of innate immunity. Here, we review current literature in hopes of stimulating research that enhances understanding of how the oxygen environment at birth influences lung development and host defense. This knowledge may help identify those children at risk for disease and ideally culminate in the development of novel therapies that improve their health.

Cell population data in neonates: differences by age group and associations with perinatal factors

INTRODUCTION

Cell population data (CPD) describe physical parameters of white blood cell subpopulations and are reported to be of some value in the diagnosis of sepsis in neonates. Before using the CPD for diagnosing sepsis, the baseline features of the CPD distribution in healthy neonates should be clarified. The aim of this study was to compare the CPD distributions of healthy neonates and other age groups and to identify perinatal factors that are associated with changes in the CPD distribution of healthy neonates.

METHODS

The CPD distribution of 69 samples from term neonates was compared with adolescents and adults. The CPD distribution of 163 samples from healthy neonates was analyzed in association with perinatal factors, including gestational age, chronologic age, birthweight, delivery mode, premature rupture of membranes, diabetes, and pregnancy-induced hypertension.

RESULTS

The CPD distribution for term neonates was significantly different from those in adolescents and adults. The mean lymphocyte volume showed a negative correlation with gestational age at birth (r = -0.305; P < 0.01). The mean neutrophil volume was smaller in the cesarean section group than in the normal delivery group. The small for gestational age (SGA) group had smaller mean neutrophil volume and mean monocyte volume than the appropriate for gestational age group.

CONCLUSION

The CPD distribution of healthy neonates differed from those of adolescents or adults, and the differences were associated with gestational age, delivery mode, and being SGA.

Use of granulocyte colony-stimulating factor during pregnancy in women with chronic neutropenia

OBJECTIVE

To report outcomes associated with the administration of granulocyte colony-stimulating factor (G-CSF) to women with chronic neutropenia during pregnancy.

METHODS

We conducted an observational study of women of childbearing potential with congenital, cyclic, idiopathic, or autoimmune neutropenia enrolled in the Severe Chronic Neutropenia International Registry to determine outcomes of pregnancies, without and with chronic G-CSF therapy, 1999-2014. Treatment decisions were made by the patients' personal physicians. A research nurse conducted telephone interviews of all enrolled U.S. women of childbearing potential using a standard questionnaire. Comparisons used Fisher's exact test analysis and Student's t test.

RESULTS

One hundred seven women reported 224 pregnancies, 124 without G-CSF therapy and 100 on chronic G-CSF therapy (median dose 1.0 micrograms/kg per day, range 0.02-8.6 micrograms/kg per day). There were no significant differences in adverse events between the groups considering all pregnancies or individual mothers, for example, spontaneous terminations (all pregnancies: no G-CSF in 27/124, G-CSF in 13/100; P=.11, Fisher's exact test), preterm labors (all pregnancies, no G-CSF in 9/124, G-CSF in 2/100, P=.12). A study with at least 300 per group would be needed to detect a difference in these events with 80% statistical power (α=0.05). Four newborns of mothers with idiopathic or autoimmune neutropenia not on G-CSF (4/101) had life-threatening infections, whereas there were no similar events (0/90) in the treated group, but this difference was also not statistically significant (P=.124). Adverse events in the neonates were similar for the two groups.

CONCLUSION

This observational study showed no significant adverse effects of administration of G-CSF to women with severe chronic neutropenia during pregnancy.

LEVEL OF EVIDENCE

III.

Neutropenia in the newborn

PURPOSE OF REVIEW

The aim is to review normal blood neutrophil concentrations and the clinical approach to neutropenia in the neonatal period. A literature search on neonatal neutropenia was performed using the databases PubMed, EMBASE, and Scopus, and the electronic archive of abstracts presented at the annual meetings of the Pediatric Academic Societies.

RECENT FINDINGS

The review summarizes current knowledge on the causes of neutropenia in premature and critically ill neonates, focusing on common causes such as maternal hypertension, neonatal sepsis, twin-twin transfusion, alloimmunization, and hemolytic disease. The article provides a rational approach to diagnosis and treatment of neonatal neutropenia, including current evidence on the role of recombinant hematopoietic growth factors.

SUMMARY

Neutrophil counts should be carefully evaluated in premature and critically ill neonates. Although neutropenia is usually benign and runs a self-limited course in most neonates, it can be prolonged, and it constitutes a serious deficiency in antimicrobial defense in some infants.

Neonatal host defense against Staphylococcal infections

Preterm infants are especially susceptible to late-onset sepsis that is often due to Gram-positive bacterial infections resulting in substantial morbidity and mortality. Herein, we will describe neonatal innate immunity to Staphylococcus spp. comparing differences between preterm and full-term newborns with adults. Newborn innate immunity is distinct demonstrating diminished skin integrity, impaired Th1-polarizing responses, low complement levels, and diminished expression of plasma antimicrobial proteins and peptides, especially in preterm newborns. Characterization of distinct aspects of the neonatal immune response is defining novel approaches to enhance host defense to prevent and/or treat staphylococcal infection in this vulnerable population.